What we have developing is a very powerful negative NAO pattern. Theres a powerful ridge developing over Greenland which is causing an upper level low to develop and stall over the NE US . This upper level low if forcing a huge trough down the eastern US which is opening the door for cool Canadian air to come south , which will lead to temperatures well below normal through most of this upcoming week.
Meanwhile this upper level low will send disturbances from NW to SE with cold pools aloft, this mixed with daytime heating will lead to potential for scattered showers and thunderstorms everyday, especially in the afternoon. Our first disturbance/cold front can be seen today over Northern PA on the radar above.
That line of showers and storms will come SE through the forecast area late this afternoon through early evening and then weaken and dissipate by late evening, lows in the mid 40s interior to mid 50s expected
This will be the case tomorrow and everyday this week and these disturbances will act like cold fronts, keeping below average temperatures through the week. Any activity that develops during the day will weaken at night with quick loss of daytime heating
Tomorrow with clouds and showers around, plus the cold front passage tonight will only be in the low 60s interior to mid to upper 60s elsewhere
Tomorrow afternoon another disturbance is coming through with more scattered showers and thunderstorms, nothing should be severe but with very cold air aloft, some hail is possible with any storms along with heavy downpours
Again activity will dissipate going into the night-time and lows again will range from the mid 40s to mid 50s
Tuesday, Wednesday and Thursday will be nearly identical with showers possible each afternoon, we have to now cast each of these disturbances as some will be more powerful than others, so with some maybe only a few scattered showers are possible but with others widespread showers and thunderstorms.
Highs in the low 60s to upper 60s and lows in the mid 40s low to mid 50s , tempertures 5-10 degrees below average before the trough eventually tries to exit next weekend, where then our next ridge of high ressure tries to build in leading to return of warm to even hot weather by early next week, let the roller coaster ride begin.